diff options
| -rw-r--r-- | lib/line-index/src/lib.rs | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/lib/line-index/src/lib.rs b/lib/line-index/src/lib.rs index 527ba08717a..c0e526a8e0f 100644 --- a/lib/line-index/src/lib.rs +++ b/lib/line-index/src/lib.rs @@ -141,10 +141,15 @@ impl LineIndex { /// /// If the offset is invalid. pub fn line_col(&self, offset: TextSize) -> LineCol { - let line = self.newlines.partition_point(|&it| it <= offset) - 1; - let line_start_offset = self.newlines[line]; + self.try_line_col(offset).expect("invalid offset") + } + + /// Transforms the `TextSize` into a `LineCol`, or returns `None` if the `offset` was invalid. + pub fn try_line_col(&self, offset: TextSize) -> Option<LineCol> { + let line = self.newlines.partition_point(|&it| it <= offset).checked_sub(1)?; + let line_start_offset = self.newlines.get(line)?; let col = offset - line_start_offset; - LineCol { line: line as u32, col: col.into() } + Some(LineCol { line: line as u32, col: col.into() }) } /// Transforms the `LineCol` into a `TextSize`. |